1. Field of the Invention
This invention relates to a proxy server apparatus for providing communication between a network and a server via a public telephone network connected to the server, a proxy server system including a plurality of server apparatuses, and the server coupled to the network via the proxy server and the public telephone network.
2. Description of the Prior Art
Generally, in the TCP/IP communication, when a client requests connection to a server, a connection can be provided by specifying the IP address of the server. However, due to the popularization of the Internet, the network becomes big and there are many servers, so that it becomes difficult to control all IP addresses of servers. Thus, DNS (Domain Name Services) has been developed.
A DNS server searches an IP address from the specified name of the server. Thus, when connection is made to a server without directly specifying the IP address of the server a DNS server searches the corresponding IP address from specified name of the server. FIG. 9 is a prior art table controlled by the DNS server. In the DNS, names of servers coupled to the network correspond IP addresses one to one, that is, the IP addresses have been determined in advance.
In that structure, it is necessary that the server has an IP address previously determined and is always connected to the network. If the server is provided within a public area, there is no problem in this structure. However, if a server is provided in a home, it is necessary to connect to the network through a public telephone network and if it is always connected to the network, a telephone charge is high. When a server in a home, the number of times of accessing per unit interval is not so high. Accordingly, it is desirable desired to connect the server to the network only when there is a necessity for connection to suppress the telephone charge.
Moreover, in the case that the general home use computer is connected to a network through a public telephone network, the PPP (Point to Point Protocol) is used. In the PPP connection, because the number of the IP addresses is limited, the home use computer does not have IP addresses and an IP address is dynamically assigned to a home use computer on connection and the address is used only while the computer is connected to the network.